Grinding machine



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'7 Sheets-Sheet l w. A SCHMIDT GRINDING MACHINE Filed sept. 1e

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W. A. SCHMIDT GRINDING MACHINE Filed Sept. 16, 192] '7 Sheets-Sheet 2WITNEESEE @mmm N nv. 2 1926. 1,605,146

w. A. SCHMIDT .GRINDING MACHINE Filed Sept. 16', 1921 '7 Sheets-Sheet 3WITNESSES 51ML aumuwl/ywwi- Z Nov. 2 192e. 1,605,146

W. A. SCHMIDT A V GRINIQINGV MACHINE- v Filed Sept. 16, 1921 7Sheets-Sheet 4 y @man1/Lkw u @Hof/vlug' /yw im 1,605,146 W. A. SCHMIDTGRINDING MACHINE 1921 7 Sheets-Sheet 5 Filed Sept 16 Nov. 2 1926.

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W. A. SCHMIDT GRINDING MAHINE vFiled sept. 1e

1921 7 Sheets-Sheet 6` Patented Nov. 2, 1926.

PATENT OFFICE. l

WILHELM A. SCIFMIDT, OF ILION, NEW YORK, ASSIGNOR TO AREMINGTONTYPEWRITER COMPANY,` OF ILION, NEW YORK, A CORPORATION OF NEW YORK.

GRINDING MACHINE.

` Application filed september 1e, 1921. sensi no. 501,151. K

My inventionrelates to machines for simultaneously grinding oppositefaces of an article interposed between a pair of grinding wheels. y y

Generally stated, one of the main objects of the invention is to providea highly efficient machine of the character specified.

` More specically stated;=the objects of the invention may be said to beas follows 1st. To so mount the oppositely arranged grinding wheels thatthe aXes thereof may be disposed out of alignment, and provide not onlyfor grinding the article. but to enable the grinding wheels to beeffectively dressed, one by the other.

2nd. The provision of an leflicient work holder which has a freedom ofmovement in certain directions and is controlled or restrained in itsmovementin such direction by the directaction of the grinding faces ofthe wheels on the article supported by said holder'.

3rd. The provision of efficient mounting means for the grinding wheelsso that they may be moved relatively towards and away from one anotherand the grinding may be effected with great precision.

lith. The provision of efficient means for controlling the relativemovements of the grinding wheels in the grinding and dressingoperations.

5th. The provision of efiicient and accurate gaging means for the wheelsin both the grinding and dressing operations.

th. The provision of comparatively simple, reliable and efficientautomatically operating means for controlling the cycle of operationseffected in grinding an article.

7th. The provision of single and effective means for bringing a` supplyof liquid to the grinding wheels.

8th. The provision of simple and effective means for preventing injuryor breakage in the power transmitting means and assuring a proper andaccurate grinding operation.

9th. The provision of an automatic control of the work holder withoutinterfering with the floating character thereof.

10th. The provision of various details of construction which contributeto the production of an accurate and highly efficient grinding machine.I

To the above and other ends which will hereinafter appear, my inventionconsists in al view of the upper portion of the machine taken on theline 3-3 of Figure 1 and lookng in the` direction of the arrows at saidine.

Figure 4 is a corresponding detail sectional view of thelower portion ofthe machine with parts omitted, the view illustrating the cam andconnections for the fioating work holder..

Figure 5 is a detail fragmentary vertical sectional view taken centrallythrough the right-hand spindle-carrying head on the line 5 5 of Fig. 2and looking in the direction of the arrow at said line.

Figure 6 is a fragmetary detail horizontal sectional view of the stopmeans for limiting the relative movement of the heads towards each otherin the grinding operation, the section being taken on the line 6 6 ofFigure l. and looking in the direction of the karrow at said line.

Figure 7 is a detail transverse sectional view of the. grinding wheelsshowing the manner of mounting the same on their4 respective spindles.

Figure 8 is a detail fragmentary fore-andaft vertical sectional viewshowing the cam and connections for moving the right-hand grinding wheelaxially, the section being taken on the line 8-8 of Fig. l and lookingin the direction of the arrow at said line.

' Figure 9 is a fragmentary detail side elevation with parts broken awayand showing a portion of the work holder with an article clamped inplace. f

Figure 10 is a detail transverse sectional view of the same taken on theline 10-1() of Figure 9 and looking in the direction of the arrow atlsaid line.

Figure l1 is -a'detail transverse sectional view of the same taken onthe line lll-11 of Figure 9 and looking in the direction of the arrow atsaid line.

Figure l2 is a fragmentary detail vertical transverse sectional view,with parts omitted, of a portion of the work holder, the view being'taken on the line 12,-12 of Figure 3 and looking in the direc-tion ofthe arrow at said line.

Figure 13 is a detail top plan view of the frame, which supportsthe'floating work holding devices.

Figure 14 is a detail fragmentary rear elevation of one of the workholding devices with a type bar secured in place therein.

Figurel is a detail diagrammatic view looking endwise of thefs'pindlesof the grinding wheelsand showing the.l relative disposition of thetwobppositely disposed grindingwheels with the axes thereof out, 0falignment.` v`

' Figures 16 and 17 are diagrammatic front elevations of a`workholdingdevice with a type` bar secured thereto, the views showingrespectively, and very much exaggerated, dtferent :parallel and angularpositions a work holding device and the type bar carried thereby -mayassume, as the parts are viewed from the front of the machine.

Figure 1S is a likeview of the same showing different angular positionsthe parts may assume as viewed from above.v

My invention is shown, inthe present instance, embodied in a machineVdesigned to simultaneously grind the opposite' parallel. fiatbearingiface's on the heel or pivot-end portion of 'a sheet metal typebar intended to be received in a bearing slot of 'a type bar segment ofa typewriting machine. It should be understood,ihowever, thatA theinvention is notrestricted to its embodiment in such a machine andthatthe machine shown may be 'employed wherever found available. Icontemplate embodying features of vmy invention in ltwo formsv ofmachines, one a so-called hand machine in which the various operationsare controlled by hand, and the other asd-called automatic machine inwhich a complete cycle of operations in grinding a type bar isautomatically effected; f l

I will first describe the automatic machine, and will then refer to vthehand machine indicating' wherein the automatically controlled parts ofthe first described machine are orf may be arranged to'be controlled bylhand,y

It sliould be borne in mind that in` grinding opposite bearing faces ofeach type bar it is essential that the faces be ground in trueparallelism to accurately co-act with thebcaring'walls of the slot inthe segment in whichthe type bar is received and pivoted. It also isessential that the grinding at each side of the bar be only to a givendepth so that the thickness of the bar at this point will be reducedfrom, say, .035 of an inch to, say, .03e of an inch, and will properlyfit within its guide slot and coact properly with the side wallsthereof. Vilith a consideration in mind ofthe great requiredl ingrinding the articles it will be understood how necessary it is toprovide efficient means for mounting the grinding wheels and work holderand for controlling and gaging the movements thereof and for accuratelybringing about an laction ofthe grinding wheels on the work.

is shown in the present instance the machine may be said to comprise twooppositely disposed cup-shaped grinding wheels mounted on spindles orshafts arranged end to` end andout of alignment, and movable axiallyrelatively one to the other to effect a relative movement. of the wheelstowards and away from one another into and out of grinding position withreference to the article to be ground, and also into and out ofco-'action with each other to effect a dressing of the grinding faces'ofthe two wheels one on the other. :A floating work holder carries a typebar to be ground between opposing parallel faces of the grinding wheelsand maintains it in such position during the grinding operations.lfowever, the construction and mounting of the holder is such that thetype bar has a freedom of movement axially of the shafts on which thevf'hce'ls are mounted and at various angles to the shafts, and iscontrolled and restrained in such movements only by the direct contactlof the article to be ground with the parallel grinding faces of thewheels. llVhen, therefore, the 'wheels are brought towards each otherthe interposed floating type bar is'automatically brought into properparallelism with the faces of the grinding wheels by the direct actionof said faces of the wheels themselves on the type bar, and the grindingaction isv .properly applied and equally distributed in parallelism onboth sides of the type bar. As will hereinafter appear, means areprovided for controlling the movement of the work holder,`with the worksupported thereby, into and out of operative position, and for contrlling the relative axial movements of the wheels into and out ofgrinding position, and for gaging the movements of. the wheels againstthe work,

As shown in` the present instance, the frame l of the machine whichsupports various working parts, has a bed 2 formed with longitudinallyextending ways 3 on which spindle carrying heads 4 and 5 are mounted foradjustment towards and from each other. A screw 6 turns'in a bearing ina bracket 7 secured by screws 8 to the righthand Yend of the bed Thethreaded portion of-this screw is received in a tapped opening` in thehead 4 and controls the adjustment ot the latter along the ways 3. Theadjustment ot the lett-hand head 5 is controlled in a like manner by a'correspending screw 10.

Referring particularly to Fig. 5, it will be seen that the drivingspindle or shaft 11 of the right-hand grinding wheel 12 turns inadjustable bearings contained within a quill or hollow supporting member13 that is mounted for independent longitudinal movement in theright-hand supporting head 4 and constitutes an oil containing chamberin which the spindle turns.4 The head 4 carries two two-part surroundingsupports tor the quill 13, each comprising a section 14 held to itscompanion member 15 by screws 16. An oil chamber 17 is formed in eachmember 14, access being had thereto through an oil opening 18 ordinarilyclosed by a screw plug 20. The quill 13 is prevented from turning in itsbearing in the head 4 by a spline 21 received in a spline groove 22 thatenables the quill 13, nevertheless, to receive bodily longitudinalmovement with the parts carried thereby independently ot the supportinghead 4. An oil opening that is normally closed by a screw 23 leads tothe interior oll the quill, and through this opening oil may beintroduced to about one-halt the height of the quill so that thatportion ot the spindle 11 contained in the quill may turn in a bath ofoil. Suitable bearings 24 within the quill receive and support thespindle 11 and are provided with inclined outer surfaces surrounded bymembers 25 having corresponding co-acting inner inclined surfaces. Anadjustable collar 26 has a threaded connection with a companion member25 to effect an adjustment of the latter and thereby adjust theassociated member 24. An end plate or head 27 centrally apertured forthe passage ot the spindle 11 therethrough, is secured to the rightshandend of the quill 13 by screws 28. An end plate orhead 30 is secured byscrews 31 to the lett-hand end of the quill, and is provided with athrust bearing 32 which coacts with a flange 33 on the spindle.Contained within the quill 13, and loosely surrounding the spindle 11,Ais a flanged collar 34 that bears against a part 35 lixedlyY secured tothe quill. A coiled expansion spring 36 surrounds the spindle and bearsat one end against the flanged collar 34, and at its opposite endagainsta lianged collar 37 that loosely surrounds the spindle. Theright-hand face of the collar 37 bears against anti-friction balls 38,which in turn bear against a flanged collar 4() that surrounds thespindle and is secured thereto by a screw 41. The balls 38 are receivedin a ball spacer 42 that is free on the shaft. rlhe etlect off thisconstruction is to exert the torce of the spring 36 through the antifriction balls against the spindle tending to torce the latterlongitudinally to the right in its bearings and to maintain the flange33 on the spindle against the thrust bearing 32.

The inner end portion of the spindle 11 is, as best shown in Figu7,formed with a seat for a key 44 which connects a disk 45 to turn withthe spindle. One side of the disk bears against the flange 33 on theshaft, whereas one side of the cup-.shaped grinding wheel 12 bearsagainst the opposite tace of the disk. The spindle is slottedlongitudinally at 43 toreceive a spline projection 47 of a centrallyapertured disk 43, to ixedly connect the latter to turn with thespindle.

This disk 48 bears against the" opposite side of the wheel`12 and isclamp-ed in. place by a disk 50 having a tapped central opening by whichit may be screwed into place on the threaded end 51 oit the spindle, andthus lirmly hold the wheel 12 on its driving spindle. Rotation istransmitted to the right-hand grinding wheel 12 by a pulley 52 supportedon'the head 4 independently of the spindle 11 but operatively connectedto the spindle so as to cause the latter to turn with the pulley butenable the spindle to move longitudinally with the quill 13independently ot the pulley. Thus the pulley 52 is mounted on bearingballs 53 through bearing members 54 on the pulley. Bearing members '55on which the balls roll are supported on a liange supporting sleeve 56secured to a bracket 57 on the head 4 by screws 58, screws 59 connectingthe bracket 57 to the head. A centrally apertured end plate or disk 30tits over the supporting sleeve 56, and has a projection 61 that isreceived in a longitudinally extending groove 62 in the bearing sleeveso as to prevent the plate from turning on the supporting sleeve. A locknut 63 is screwed onto the threaded end 64 of the supporting sleeve 5Gand retains the pulley against removal therefrom. An oil opening 65 inthe pulley, normally closed by a screw 66, communicates with thebearings oLt the pulley on its fixed support. A connecting member G7 iskeyed to the outer reduced end portion of the spindle 11 and is held inplace thereon Iby a nut 68. This member 67 comprises two arms' thatextend in opposite directions trom the spindle and are received at thefree ends thereof in grooves, ways or slots 70 formed in the in-A is nottransmitted to the spindle 11, or exerted thereon transversely of itsaxis.

F rom certain aspects of my invention any suitable means whether handactuated or automatically operating, may be employed to move the quill13 and the parts carried thereby axially to move the grinding wheel 12towards and away from its companion grinding wheel. In the presentinstance l have illustrated, as shown in F ig. 5, a sleeve 72 which isslit at 73 to form to a clamping member in the nature of a split ring orcylinder'. This member surrounds the quill intermediate the two sets ofsupports 14 and 15 and is clamped tight on the quill by screws 74;.rlhese screws pass freely through openings in a flange 75 that projectsrearwardly from the sleeve 72 above the split 73 therein, and engage inthreaded openings in a corresponding flange 7 6 below the slit 73. Theunderside of the sleeve is formed with a recess in which is seated twobearing blocks 77 held in place by screws 78. These bearing` blocksco-act with the upper rounded end of a crank arm 80 secured to a rock'shaft 81 extending fore-andaft from front to rear of the machine andmounted in bearings in the head 4. The forward end of. this shaft issquared, as indicated at 82 in. Figs. 1 and 2, to receive a landmanipulated crank not shown), should it be desired to control the axialmovement of the spindle 11 b v hand. However, in the present instance Ihave provided means for automatically controlling the rock shaft 81,quill 13 and the axial movement of the spindle 11 and grinding` wheel 12carried thereby, as will hereinafter clearly appear.

It is unnecessary to move both of the grinding wheels axially towardsand away from each other in order to obtain an eifective grinding ofopposite parallel faces of the article to be ground, or in order todress the grinding faces of the wheels one by the other. Therefore, itis unnecessary to provide an axially movable quill for the spindle 83 ofthe left-hand grinding wheel 84, the latter remaining fixed againstaxial movement on its head 5. However, aside from the fact that thequill of the right-hand head l is movable axially, whereas the lefthandquill 13a is held fixed on its head5, and has no means connectedtherewith for moving it and the parts carried thereby axially, thebearings for both spindles and the driving` connections with theirpulleys, etc., are substantially identical. .A detailed illustration anddescription of the mounting for the left-hand wheel would amountpractically to a repetition of that already given, and' it is thereforedeemed unnecessary. Where corresponding parts are shown at both sides ofthe machine, they will be indicated by corresponding reference numerals.

rlhere is one important point to be observed, however. s the machine isshown in the present instance, the two spindles 11 and 83 are arrangedend to end but are maintained out of axial alignment, their axes beingparallel and arranged one above the other, so that the grinding wheels12 and l841 are eccentrically arranged with reference to each other,asindicated in Fig 15. This arrangement is of importance in dressing,truing or facing the wheels by their mutual action one on the other, aswill be hereinafter more fully brought out, but is unimportant so far asthe grinding operation is concerned. For the latter purpose it isimmaterial whether the spindles 11 and 83 are arranged end to end inalignment or are arranged with their axes parallel as shown. Therefore amachine may be so constructed that the axes of the spindles 11 and 83are held in alignment for the grinding operation but may be shiftedlaterally relatively one to another to bring their axes in parallelarrangement and held in such arrangement during the truing or dressingoperation.

The means shown in the present instance for automatically moving theroclr shaft 81 and thus controlling the relative axial movements betweenthe grinding wheels 12 and 8st comprises an angular lever, designated asa whole by the reference numeral 85 and best shown in Figs. 1 and 2.This lever is pivoted to turn freely on the rear end portion of the rockshaft 81 and is provided with a yokelilre depending' arm 86 carryingoppositely disposed set screws 87 with lock nuts 88 thereon. Fixedly,though detachably secured to the rock shaft 81 is a hub 90 provided witha bifurcated extension 91 in which is fitted the upper end of aresilient member or spring arm or plate 92 that is secured in placebetween the arms of the bifurcated extension by screws 93. The lowerfree end of this spring arm 92 eirtends down between the set screws 87.The construction is such that the only connection between said arm 86and the rock shaft 81, by which motion is transmitted from the former tothe latter, is through the set screws 87 bearing on the spring arm 92,and the purpose of which will hereinafter more clearly appear'. Thehorizontally disposed arm of the bell crank lever 85 is pivotallyconnected to a depending link 941. The low-r end of this linlr 94 is inturn p'ivotally united to aroclring arm 95, as is best shown in Fig. 8.The arm 95 is pivoted at 90 to the frame 1 of the machine and has aforwardly projecting member or arm 97 which carries a laterallyprojecting anti-friction roller 98 atthe free end thereof. This rolleris received in a cam groove 100 in one side of a cani wheel 101 lixedlymounted on cam shaft 102. The cam shaft 102 is mounted in suitablebearings in the frame of the machine iii? and extends transverselythereof beyond the right-hand side of the frame where a worm wheel 103is secured thereto. The worm wheel meshes with a worm 104 on a shaft 105mounted in bearings in a frame 106. This frame is pivoted at 107 (Fig.2) to afford a bodilyv lateral movement of the worm shaft around thepivot 107 in order to throw the worm 104 into and out of mesh with theworm wheel 103. "The rear end portion of the worm shaft 105 has a bevelgear 108 secured thereto and this gear meshes with al bevel gear 109mounted on one end of a short shaft 110 which turns in a bearingsupported by the pivoted frame 106. The inner end of the shaft 110 has adriving pulley 111 mounted thereon, as indicated in Fig. 1. A suitablydriven belt 112 is received on and coacts with the pulley 111 to turnthe cam shaft 102 through the intermediate train of gea-ring, andthereby effects a back and forth axial movement of the quill 13 and theparts carried thereby through the connection betweeen the rock shaft 81and the cam wheel 101.

Means are provided for automatically throwing the machine out ofoperation after it has completed a cycle of operations required tointroduce a type bar in place, grind it and remove the ground bar. Thisinvolves the throwing out of operation of the cam shaft 102, so as toarrest the movements of thev parts by which axial movements of theright-hand grinding wheel 12 is eected. In order to bring this about Ihave provided a cam 113 on the outer face of the worm wheel 103. Thiscam coacts with a roller 114 carried by an arm 115 secured to a rockshaft 116. This shaft is mounted in suitable bearings on the right-handend of the frame 1 and carries a depending arm 117 provided at its lowerend with an angular cut-out 118, as shown in Fig. 1, to receive anangular portion 1.20 at the forward end of the worm shaft 105. When thearm 117 is in the position shown in Figs. 1 and 2, the worm shaft willbe supported in its elevated position, maintaining the worm 104 inengagement with the worm wheel 103 and rendering effectivethe operativeconnections from the pulley 111 to the quill 13 which carries theaxially movable right-hand driving spindle 11.. The hub of the arm117has an upwardly extending projection 121 which coacts with a plunger 122pressed outwardly by a spring 123 contained within a guide sleeve 124 inwhich the plunger is received and works and which is iixed to the frame1 of the machine. The force thus exerted by the spring 123 tends tomaintain the arm 117 in a position where it will engage the shaft 105and maintain the pivoted supportingy frame elevated with the worm andworm wheel in mesh. Vhen, however, the cam 113 reaches the roller 114,the lower end of the arm 115 is moved to the right, thus rocking theshaft -116 and withdrawing the lower hoolclike end portion of thearm 117from beneath the shaft 105. The frame 106 is then free to turn aroundits pivot 107, lowering the worm 104 and disengaging it fromr the wormwheel, thus automatically disconnecting the operating means for the camshaft 102 and arresting the axial movement of the right-hand grindingwheel.

The extent of this disengaging movement of the worm, through the pivotalmovement of the frame 106, is limited and determined by a link 124pivoted at its lower end,'at 125, to the frame 106, and at its upperend, as at 126, to a lever 127 provided at its forward end with a handle128 by which it may be controlled. This lever is pivoted to the frame ofthe machine at 130 and the downward movement at the rear end thereof islimited by a set screw 131 carried thereby and coacting with the stoppin 132, carried by frame 1. In'order to reestablish the driving`connection between the worm shaft 105 and the cam shaft 102, it ismerely necessary to depress the handle 128, thereby turning the frame106 on its pivot 107 and elevating the worm 104 into mesh with its wormwheel 103. At this time the hoo-k like lower end of the arm 117 willengage beneath the forward end of the worm shaft and lock it in itselevated position until a complete cycle of operations has taken place,when the cam 113 will again be effective to automatically disengage thearm 117 and enable the worm to be disengaged from the worm wheel, and anarrest of the cam shaft to be eifected.

I provide meansY for limiting the axial movement of the right-handgrinding wheel 12 into grinding relation with the type bar and towardsthe wheel 84, and thus accurately determine the depth of the grindingoperation and the thickness to which the article is ground. For thispurpose I provide gage or stop devices which are best shown in Figs. 1,2 and 6. The devices4 in question co-mprisea so-called interponent orstop 133 that corresponds in thickness to the thickness of the articleafter the grinding operation has been effected. This interponent in thepresentV instance is shown mounted on a sup-porting member 134. Themember 134 has a cylindrical stem 135 seated in a bearing 136 on thehead 4 to turn on a horizontal axis, so that the interponent 133 inturning with the member 134 may be shifted into or4 out of operativeposition. A thumb screw 137 is seated in a tapped opening in thebearing` 136 and is adapted to bear at its end against the cylindricalstem 135 and hold the device 134 in either its operative or inoperativeposition, as de-r sired. When the device 134 is turned down to operativeposition1 illustrated in Figs.

1 and f2, the part 133 will be interposed between two stop members 138and 140. Reterring more particularly to Fig. 6, it will be seen that thestop member 138 has a reduced end portion 141 by which it may bedetachably seated in an opening 142 in the head4, whereas the stop 140is 'formed as the inner end ot a` micrometer screw 143 received inAtapped openings in torwardly projecting flanges 144 and 145 or" themember 72 which is secured to the quill 13. The head ot the micrometerscrew is provided .with indices, as indicated at 143, for cooperationwith a relatively lined pointer 147, whereas a lock nut 148 secures thescrew and its stopy 140 in adjusted position. iii/Tl en the device 134is in the operative position, with its member 133interposed between thestops 13S and 140, the extent ot movement et the quill 13, with theparts carried thereby, will be limited in theapproach of the grindingwheel 12 towards its companion grinding wheel 84, thus determining` theextent Aor depth of the grinding operation, which may be varied b`y anadjustment of the microme `eter screw 143. 1t has hereinl'ietore beenpointed out that the axial movement of'` the right-hand grinding wheel12 is transmitted throughI the resilient member 92, and it should4 beunderstood that the parts are so adjusted, constructed and arranged thatprior tothe arrest .of the axial movement ot' the grinding wheel 12 4bythe stops 133, 138 and 140, the resilient member 92will be flexed,exerting its torce to hold the stops in contact and to lpress thegrinding l'ace of the wheel 12 against the article to be ground. itwillthus be understood that when the stops 133, 138` and 140 coact toarrest the axial movement of the right-hand driving wheel 12, the force'of the positively actuated connections from the cam 101 is efr- ,ertedthrough the resilient .member 92, and there is an assurance ot' theproper extent ot axial movement of: the wheel, witbout at the same timethere Ybeing any liability ot injuring the construction. or the lack ot(proper. extent oil movement due to wear on the parts orlooseness in theconnect-ions, etc. When it is desire(q .to dress Vor face the wheels onebyI another, it is merely necessary tri-turnthemember .34 out oroperative position where its part 133 is interposed bejtween, the stops138 4and 1*-1-0, thus enabling the. grinding faces met the. wheels to bebrought into Contact witheach other. The stops 13S and 140 at this timelimit the aiial movement of the wheel 12 towards the wheel l8:1but anadjustment of the stop Y140 en,- ables the extent of this movement to bevariedat will'. v l o ,By arranging the .axes lof the wheels out ofalignment in the manner shown and described, itwill be understood thatevery point on the grinding face a of the Wheel 12 will cut crosswise atevery point on the grinding face a of the wheel S4, and vice versa, aswill be clearly understood from a consideration of Fig. 15. 1t istherefore possible to effectively dress the grinding races oi the wheelsone by another, and to dress or true the faces of the wheels accuratelyand in parallelism.

I will now `describe the floating work holder by which the articles tobe ground may be automatically interposed between the grinding wheels;may be moved baclr and ttorth during grinding Operation; and may beremoved froml between the grinding wheels after the article is ground.

Referring more particularly to Figs. 1, 2 and 3 and 9 to 14, inclusive,it will be seen thata type bar A., or other article to be ground, isadapted to be seated in a grooved seat 149 in one side ot a work holdingdevice 150. The article is clamped in place in its seat by a clamp orContact device 151 lixed by its hub to a cylindrical stem 152 which isadapted to slide lengthwise in a bearing 153 inthe member 150 as thecontact device 151 moves into and out of clamping engagement with thearticle to beground. The hub ot the clamp is also mounted to .slide in abearing 153a in the holding device. The stem 152 projects through to apoint at the op positeside yof the device 150,. and at its end portionis formed rectangular in cross-section, as indicated at 154. Thisrectangular end portion extends through a corresponding opening in abowed or arched spring' 155 formed `as indicated in Figs. 10 and 14,sothat the central portion of the spring is flat while the free endportions thereof are bent so as to bear against one side ot the workholding device 150. A pin 155"L projecting from a side of the holdingdevice passes through an opening in the spring 155 and prevents it andthe clamping member from turning. A hand actuated controlling member 156is pivoted at 157 to the rectangular portion of the stem, the free endol2 the controlling member 156 constituting a linger piece by which itmay be moved on its pivot 157 from the full to the dotted line positionindicated in Fig. 14, or vice versa. rFhe controlling member 156 is inthe nature of a lever formed with a cam or enlargement 158,. 1t will beseen that the distance vtrom the pivot 157 tothe flat end portion 100 ofthe controlling member is considerably less than the ldistance from saidpivot 157 to the flat .face 161 of said member. 1n consequence of this,a movement of the controlling member 'from the dotted to the itull lineposition in Fig. 14, is elleetive to flex the spring 155 and cause theforce of the spring to be exerted vlongitudinally of the stem 152, andtov be applied through the contact 151 to the typegbar, .in order toclampl the latter in place vin its seat. 1t will be understood moreover,

that when the flat face 161 of the controlling member engages the springas shown in full lines. said controlling member` and the partscontrolled thereby will be locked or maintained in the position shown,to clamp the type bar to the holder under the force of the spring 155.When, however, the controlling member 156 is turned to the dotted lineposition the force of the spring 155 on the clamp is released, enablingthe latter to be shifted longitudinally of its stem 152 to release thetype bar and permit its removal from the holder. If desired suitableauxiliary means may be employed to aid in properly positioning andholding the type bar in place on the holder,such means for eX- ample asa sheet metal bracket 162 secured to the upper edge of the holder byscrews 163 and adapted to engage in a recess 164 formed in the type bar.4

In the present instance I employ two of these work holders 150constructed and mounted alike and the description of one applies to theother. Each work holder 150 provided with a depending stem, support orcarrier 165 by which it may be mounted to receive a pivotal movementaround a substantially vertical axis when a type bar is in the operativeposition shown in Fig. 3. Thus, upstanding coned pivots 166 connect eachwork holding device 15G-f 165'to an arm, support or carrier 167, whereasstops 168 on opposite sides of each member 165 coact with stop faces 170on the associated arm 167 to limit the rotative movement of the member15G- 165 around its pivots 166. This movement of each work holdingdevice 15(1165 around the pivots 166 I have attempted to illustrate inFig. 18. rl`his view is intended to represent the parts as they are seenwhen viewed from above the work holding device, although the extent oit'movement is shown greatly exaggerated 'in order to clearly indicate thatby this angular movement the plane of the heel b of the type bar to beground may assume different angles relatively to the axes of thegrinding wheels, for purposes which will hereinafter more clearlyrappear. vEach supporting arm 167 is supported by pivots 171, the axes ofwhich are at `right angles to the axes of the pivots 166 and connect thearm 167 to a depending link, support or carrier 172 supported by pivots173, the axes of which are parallel with the axes ofthe pivots 171. Thepivots 173 connect the link 172 with an arm or support, or carrier 174of a frame, or head designated as a whole by the reference numeral 175and pivoted on a spindle 176 to an upright primary or main support, orcarrying arm 177, which may, if desired, be provided with a handle 178.It will be observed that the supporting frame'or head 175 is providedwith two arms 174 arranged at right angles to eachother, asindicated inFig.f13, and each arm supports a link 172, an arm 167 and a work holdingdevice 150-165 Each arm 174 is provided with a depending lug or stop 179(see Figs. 3 and 12) that is received between two lugs or stops 180 onthe associated link 172. The lower end of each link is likewise providedwith two lugs or stops 181 between which is received a stop or lug 182which projects upwardly from the associated arm r167. The stops 1797and180 limit the pivotal movement of the associated link 172 around itspivots 173, whereas the lugs or stops 181 and 182 limit the pivotalmovement of the arm 167 around the pivots 171 which connect said armwith its link 172. This manner of pivoting a work holding device on asupporting arm 174 enables said device to assume the different positionsto bring the heel of the type bar into different parallel planes which Ihave attempted to represent in Fig, 16. .In this figure the parts appearas seen from the front of the machine although it will` be understoodthat the diagrammatic showing represented greatly exaggerates the extentof movements permitted. In Fig. 17 the diagrammatic showing is intendedto represent the movement of a work holder around its supporting arm 174on the pivots 173, or on the pivots 173 and 171 to such a position as topresent the heel of the type bar at different angles with reference tothe parallel grinding faces of the grinding wheels. This view representsthe parts as they would appear when seen from the front of the machine,-although it will be understood that, as in Figs. 16 and 18, the extentof movement is greatly exaggerated in order to more clearly lrepresentIthe character of movement of the floating work holder.

The supporting frame 175 has its hub notched at two `points at 900apart, as indicated at 183. Each of these notches is adapted toreceive'the engaging nose of a latch 184 pivoted at 185 in bearings onthe upright arm 177 which supports the frame 175. A plunger 186 isreceived in a guide opening 187 in apart of the arm 177 and is pressedforwardly by an 4expansion spring V188 to cause the engaging nose of thelatch to lock the carrier or supporting frame 175 against turningmovement-on its pivotal support or. spindle 176. A finger piece 190facilitates a disconnection -of the latch to enable the frame to begiven a quarter turn on its pivot 176 to move one work holding device toaposition where a ground type bar may be readily detached therefrom, atthe same time bringing a newly introduced bar to be ground, and which iscarried by the other work holding device, to a position where it may beinserted between the grinding faces of the wheels 12 and 84. In

. short the pivotal movement of the frame or llti lll'.

head 175 on the arm 177 enables one holder to replace another inposition for use.

The supporting arm 177 is provided with hubs 191 by which it issupported on a horizontal rock shaft 192 arranged parallel with thedriving spindles 11 and 83, the shaft 192 being,` supported in suitablebearings on the frame of the machine. An arm 193 has a split hub heldtogether by a screw and by means of which the hub is clamped to theshaft 192 to iixedly connect the arm 193 to the rock shaft. Said arm 193in turn is connected by a pin 1911 and a screw 195 to the arm 177 tocause the latter to turn with the arm 193 and the rock shaft 192.

Referring more particularly to Fig. 4, it will be seen that a crank arm196 is mounted by its hub 197 on the rock shaft 192 and is l'ircdlyconnected thereto by a screw 198. This arm extends rea fwardly andcarries a laterally projecting-anti-friction roller 200 which isreceived in a cam slot 201 in a cam wheel 202 secured to the cam shaft102. ln this manner the pivotal movement of the arm 177 and the partscarried thereby is automatically controlled by the cam 202. Thecharacter of the cam is such that a loaded work holder is first movedrearwardly to introduce the heel 7) of the type bar between the nrindinfaces of the wheels, as represented in Fig. 3. Then the type barreceives a slight movement fore and aft of the machine duringthegrinding` operation. After the grinding operation is completed the arm177 is moved forwardly to the limit of its motion in order to withdrawthe ground vtype bar from between the 4grindingF wheels. The operatormay then release the latch 18-1, give the frame 175 a quarter turn tobring` the other loaded work holdingv device in position to introduceits type bar between the wheels; this movement of the frame 175carrying' the work holder with the ground bar tc one side where thelatter may be readily removed and another type bar to be ground may beintroduced in its place.

l have hereinhefore pointed out that the cam shaft 102, by which thefore and aft rocking` movement of the arm 177 is effected` alsoautomatically controls the axial movement of the right-hand grinding;wheel into and out of grinding position. I also have pointed out thatthis cam shaft is controlled by the worm shaft 105 which automaticallybrings about an arrest of the cam shaft throueh an automaticdisconnection of the worm 104 from its worm wheel 103 after a cvcle ofoperations has been completed. This cycle of operations is started by adepression of the handle 128 to connect the worm and worm wheel, andconsists in first automatically moving` the arm 177 to introduce a typebar into posit-ion between the two grinding wheels; then automaticallymoving the right-hand grinding` wheel 12 against the heel of the typebar to automatically position the floating type bar with thc oppositesides thereof in parallelism with the grinding; faces of the wheels andeffect a grindingv operation; a fore and aft movement of the arm 177being;V effected during this grinding` of the type b: After the type barhas been ground the grinding wheel 12 is automatically moved to theright out of ,SWinding.;` position and the arm 177 is automatically,Qjiven a movement forward to witlnlraw the around type bar from betweenthe wheels. rlhis completes the cycle of operations and at this time thecam 113 actuates the arm 115 to release the lower end of the arm 117from beneath the worm shaft and permit an automatic disengagement of theworm 104 from worm wheel 103, thus effecting an arrest of the cam shaftand the parts controlled thereby, Aalthough the grinding` wheels may becontinuously driven from their pulleys 52.

lli-om the foregoing` description it will be understood that the heel ofeach vfloating type bar when introduced between the grindinn` wheels isfree to receive a limited extent of lateral movement, or movementlongitudinally of the axes of the grinding wheels in parallel planes asindicated in Fig. 10, or to assume different angular positions withreference to the axes of the wheels foil a limited extent as indicatedin Figs. 17 and 18, although the type bar is held rmly in position ayinst movement with the grindwheels in the direction of their turningrmovements. rfhis limited lateral movement of each work holder with itstype bar enables the type bar to be `ground to automatically accommodateitself to the grinding` faces of the wheels and accurately find itsproper position in parallelism therewith as the bar is pressed by andbetween the wheels. l't follows therefore that each articleis accuratelyground on opposite faces in parallelism between the opposing faces ofthe grinding` wheels which alone restrain the lateral movements of thearticle, and that the positioning of the article to be ground, and themaintenance thereof in parallelism with the face. of the Heels,y isdetermined wholly by the direct contact of the lgrinding faces of thewheels on the article to he ground. @ther-wise stated the floatinglcharacter of nach holder in operative position leaves the type barunrestrained for limited extent of lateral movement except for thedirect contact of the grinding;` faces of the oppositely disposedgrinding' wheels therewith` and thus enables each type bar to properlyposition itself automatically as the wheels are moved relatively towardseach other into contact with the bar, and bring the sides of the latterin accurate parallelism with the (lll faces of the wheels by the directcontact-of the latter with those surfaces of the type bar that are to beground.

l prefer to provide a longitudinal opening extending entirely throughone of the spindles 11 c1283 by which the associated grinding-` wheel.is turned in order to supply water or liquid to the interior of the cupshaped grinding wheels 12 and Se. ln Fig. 5 Al have shown such anopening 203 extending entirely through the spindle v11.y ln practice,however, l prefer to employ a corref-:ponding opening 204; through thelefthand spindle and to connect said opening` by means of'a pipe 204i-a(see Fig. 1) with a suitable source of supply by which liquid may be fedto the inner sides of the wheels. f desired a suitable valve 205 may beemployed to control the flow of liquid from the source of supply. Suchvalve may be automatically controlled from a cam 205 on the cam shaft102.

l may also kprovide suitable means for receiving liquid from the wheelsand carrying it to a suitable point of discharge. In F ig. 8, 'I haveshown a sheet metal trough 207 carried by the arm 17 7 and disposedopposite the space between the grinding wheels. This trough is adaptedto discharge into a sheet metal trough 208 carried by the'lower section209 of a two-part housing for the grinding wheels, or to dischargedirectly into a trough 210 formed in said lower section. trough 210through the housing to an outlet 211 therein and then ce to a suitablepoint of discharge. The housing for the grinding wheels is separate anddistinct from the supporting heads l and 5 and is mounted' on the ways 3of the bed 2. ln addition to the lower section 209 the housing`comprises an upper section or cover A212 arranged 'over the wheels andpivoted at 213 to the lower section 209, so that the forward end of theupper section may be swung up and rearwardly to give access to thegrinding wheels. lt will be seen that this section 212 is apertured at214twhereas the lower section has a corresponding opening 215 (Fig. 1)to receive a work holder and permit the heel of the type bar to bereceived between the oppositely disposed grinding wheels. Suitable meansmaj,vv be provided to secure the upper section 212 in place. Referringparticularly to Figs. 1 and 3 it will be seen that for this purpose Iprovide a link 216 pivoted zit its lower end, as at 217, in a slot inthe lower section 209 of the housing and threaded at its upper end toreceive a thumb nut`218. This link may be turned on its pivot into aregistering slot on the forwardly extending flange 219 of the uppersection'. When thus positioned, and the thumb nut 218 is turned downagainst the flange 219, the upper section of the housing will be firmlyheld in.'

The liquid may be conveyed from the place on its lower section. Abacking up of the thumb nut enables the4 link to be turned forward torelease the cover section of the housing.

A sheet metal cover plate 220 may be secured to each of the heads 4E and5 over the quill 13 orll.

lllhen a hand controlled machine is to be provided, the cam shaft 102,the connections between said shaft and the parts controlled thereby, theworm wheel 103, and the various parts associated therewith are omitted.The arm 177 may then be provided with suitable. stop devices 221, 222and 223 to limit the movements of the arm 177 both forwardly vand back,and the handle 178 may be employed to effect such movements of the arm.ylhe axial movements of the grinding wheel 12 is brought about by -ahand actuated crank (not shown) applied directlyto the squared end 82 ofthe rock shaft 81. Otherwise the construction and operation of the handcontrolled machine is the same as that previously described.

` Suitable means, not shown, are provided for controlling the drivingbelts ofthe pulleys 52 to turn the grinding wheels in oppositedirections in their grinding operation, and to reduce the speed `of thegrinding wheels when they are brought into Contact with each other todress the faces of the wheels by their mutual action one on the other.

From what has been said it will be understood that a work holder 150cannot move lengthwise of the main carrying arm or primary support 177,and when in use is controlled and restrained in its movements toward andfrom the axes of the grinding wheels and in the direction of rotation of'l the wheels, but is supported to move a limited distancerfree fromrestraint in every other direction, so that the direct contact of the`parallel grinding faces of the wheels with the article carried by theholder causes the article to accommodate itself to said faces and assumea position in parallelism therewith, .and receive an equal and truegrinding on both sides between the wheels.

w lt also vwillrbe understood that the construction is such that thegrinding wheels vare maintained against deviation from the true coursein which they should turn and be fed axially one relatively to another;that when occasion requires the grinding faces of the wheels may beexpeditiously dressed one by another without the necessity ofdismounting any part of the machine or altering or destroying anyadjustment ofthe parts required in grinding the type bars; it beingmerely necessary to shift the member 133A out of operative position;'that .if any adjustment of the micrometer screw 1113 is required indressing the wheels it may ordi- ;narily. remain in such `adjustedposition after the dressing` operation for effective use in grinding,or, if conditions demand, maybe adjusted as required.

Various changes may be made without departing from the spirit of myinvention, and certain features thereofI may be employed without others.

lVhat l claim as new and desire to secure by Letters Patent, is,

l. In a combined grinding and dressing machine, the combination of twogrinding wheels operative to grind parallel faces on opposite side ofthe article to be ground, means for mounting said wheels to turn onunvarying parallel axes, and automatically operatin g means foreffecting a relative axial sliding movement between said wheels into'and out of grinding relation with the article and when desired to bringthe grinding wheels eccentrically arranged ene with reference to theother into contact to dress one wheel by the other.

2. ln a combined grinding and dressing machine, the combination of twocup-like grinding wheels the grinding face of each of which is in aplane at substantially right angles to its axis of rotation and by whichopposite parallelv faces are ground on the interposed article, means formounting said wheels to turn o-n parallel axes, and autovmaticallyoperating means for effecting -a relative axial sliding movement betweensaid wheels into and out of grinding relation with the article and whendesired to bring the grinding wheels eccentrically arranged one withreference to the other into contact to dress one wheel by the other.

3. In a combined grinding and dressing machine, the combination of twogrinding wheels that turn on unvarying axes and have a relative movementin the direction of the axes on which they turn to exert pressureagainst and act on the interposed article to be ground, means forsupporting said wheels so that the grinding face of one wheel crossestransversely the grinding face of the other wheel, and means wherebysaid wheels may be brought into contact to dress one by the other.

4. In a grinding machine, the combination ofA two grinding wheels havingparallel grinding faces adapted to be moved relatively one to the otherand to simultaneously grind opposite parallel faces on the interposedarticle te be ground, a floating holder to which the article may besecured and by which it may be'brought and maintained between oppositelydisposed parallel grinding faces on said wheels, and means for mountingsaid holder so that it has a controlled movement towards and from. the.

axes of said wheels and also a limited `uncontrolled incvement betweenopposingfaces n remind-le 0f.1tlie -V other wheel to -move the vwlneels:togethery 1n' grinding relation .one

of said pwheels and longitudinally .of fsai-d axes and at differentangles thereto but Lis,-

inea-,lee

restrained against turning movement with said wheels.

5. In a grinding machine, the combination of two grinding wheels adaptedto be moved relatively one to the other and to simultaneously grindopposite faces of the interposed article to be ground, a floating holderto which the article may be secured and by which it may be brought andmaintained between oppositely disposed grinding faces on said wheels,and means for mounting said holder to turn on aries at substantiallyright angles one te another so that the article may be held restrainedagainst movement between said wheels in certain directions but haslimited uncontrolled movements between said wheels in other directions.

6. In a grinding machine, the combination of two grinding wheels havin Yoppositely disposed parallel Grinding faces by which an interposedarticle may be ground simultaneously on opposite parallel sides, aholder to which the article may be secured and by. which the article maybe introduced and maintained between the parallel grinding faces of saidwheels, and means for supporting said holder so Vthat it has a limitedfreedom of movement in certain directions controlled or restrained onlyby the parallel grinding 'faces of the wheels on the article, thusenabling the article to automaticallj-,fv find its position between andparallel to the grinding faces wholly by the pressure of the grindingfaces thereon.

7. In a ,C rindingmachine, the combination of two grinding wheels havingoppositely disposed parallel grinding faces by which an interposedarticle may be ground simultaneously on opposite parallel sides, aholder to which the article may be secured, and means by which saidholder may be shifted to introduce and maintain the article to be groundbetween the parallel grimling faces of said wheels and which enable theholder to receive a limited unrestrained lon movement between saidwheels to bring the h varranged end to .endlbut-out of axial' alignment,a grinding wheel. carried by each spindle and between which the articlemay be received ya-nd ground by said wneels arranged on'e eccentricallyof the other, and a hollow oil containing bearing member supporting-oneof said spindles in a bath of oil and mounted for axialsliding movementwit-hits spindle towards and away from the fill against the other orseparate them, whereby the wheels may be dressed one by the other.

9. ln a combined grinding and dressing machine, the combination of twospindles arranged end to end but out of axial alignment, a grindingwheel carried by each spindle and between which the article may bereceived and ground by said wheels arranged one eccentrically oi ytheother, a bed, a head adjustable along said bed, and a bearing membersupporting one of said spindles and mounted l'or axial sliding movementwith its spindle on said head towardskand awayv from the spindle ot theother wheel to move the wheels together into grinding relation with theinterposed article to Abe ground or separate the wheels, and also toenable the wheels to bear one against the other to dress them one on theother.

lO. ln a combined grinding and dressing machine, the combination ot twospindles arranged end to end but out ot' axial alignment, a grindingwheel carried by each spindle and between which the article may bereceived and ground by said wheels arranged one eccentrically ot theother, a bed, a head adjustable along said beda bearing membersupporting one ot said spindles and mounted for axial sliding movementwith its spindle on said head` towards and away irom the spindle ot theother wheel to move the wheels together into grinding relation orseparate them, a bearing on said head, a driving pulley mounted on saidbearing, and a pin and slot connection between said pulley and theassociated spindle and by which the spindle is turned by the pulley butan axial movement of the spindle independently of the pulley may beeitected.

ll. ln a combined grinding and dressing machine, the combination ot twospindles arranged end to end but out of axial alignment, a grindingwheel carried by each spindle and between which the article may bereceived and ground by said wheels arranged one eccentrically of theother, means lor mounting said spindles with the wheels thereon forrelative axial sliding movement toward and away troni each other, and aninterponent movable into and out of vcooperative relation with. a partthat moves axially with one ot said spindles and is adapted to arrestthe axial movement thereet, said interponent when moved out ofcooperative relation permitting the wheels to bear one against the otherto dress the wheels. y

l2. ln a combined grinding and dressing machine, the combination of twospindles arranged end to end but out ofaXial alignment. a grinding wheelcarried by leach spindle and between which the article may be receivedand ground by said wheels arranged one eccentrically of ythe other, abearing member supporting one of said spindles and mounted for aXialsliding movement with its spindle towards 'and away from the spindle ofthe other wheel, an interponent movable in to and out of cooperativerelation with a part carried by said bearing member and adapted toarrest the latter in its axial m vement, and means for eiiecting anadjustment ot said part to different set positions on said bearingmember; i

13. ln a combined grinding and dressing machine, the combination or' twospindles arranged end to end, a grinding wheel carried by each spindleand between which wheels the article may be received and ground by saidwheels, a bearing member supporting one of said spindles and mounted foraxial sliding movement with its spindle, a part carried by andadjustable Yto diilerent set positions on said bearing member, and aninterponent movable into and out ol co-operative relation with said ad-ljustable part and adapted to co-act therewith to ar est the bearingmember in its axial movement, said interponent when moved ont otco-operative relation permitting the wheels to bear one against theother to dress the wheels. Y

14. ln a combined grindingand dressing machine, the combination of twospindles arranged end to end, a grinding wheel carried by each spindleand between which wheels the article may be received and ground, ahollow oil containing bearing member snpporting one of said spindles ina bath'oi oil and mounted for axial sliding movement with its spindletowards and away from the spindle of the` other wheel to move the wheelstogether in grinding relation or serparate them, a part carried by saidbearing member, an interponent movable into and out of coi-operativerelation with said part and adapted to co-act therewith to arrest theaxial movement of said bearing member and the parts carried thereby, andmeans tor affording an adjustment of saidpart to different set positionson said bearing member.

15.111 a combined grinding and dressing machine,the-combination of twospindles arranged end to end, a grinding wheel carried by each spindleand between which wheels the article may be received and ground, a bed,a head adjustable along said bed, a bearing member supporting one ofsaid spindles and freelyy mounted for axial sliding movement with its;spindle en Said head towards and away from the spindle of. the otherwheel to move said wheels together into grinding relation or to separatethem, and an interponent movable into and out of operative position andadapted to arrest said bearing member and the parts carried thereby intheir axial movement or leave them free from arrest by said interllOllli

ponent so that one wheel may coact with the other to dress the wheels.

lli'. In a combined grinding and dressing machine, tho combination oftwo spindles arranged end to end, a grinding wheel carried by cachspindle and between which wheels the article may be received and ground,a bed, a head adjustable along said bed, a bearing' member` supportingone oit said .pindles and mounted lor axial sliding niovenient with itsspindle on said head towards and away from the spindle o'l' the otherwheel to move said wheels together into grinding relation or to separatethem, a bearing lined on said head, a driving pulley mounted on saidbearing, and a pin and slot connection between said pulley and theassociated spindle by which the spindle is turned by the pulley but anaxial movement otl the spindle independently of the )alley may beeffected,

l. ln a grinding machine the combination ot a pair of oppositelydisposed grinding wheels between which an article is received and bywhich the article is simultaneously ground on opposite faces, means forctlecting a relative axial movement between the grinding wheels to causethem to coact with the article to be ground, and means tor supporting`the article to be ground', said last Vmentioned means comprising anautomatically actuated pivoted arm, a holder to which the article to beground may be secured, and intermediate connections between. said holderand arm that enable said holder to move to different parallel planes andto different angular positions relative to said planes but which)reventa the holder from moving lengthwise t said arm, a pivotalmovement of said yrin moving the article to be ground towards ant. fromthe axes ot' said wheels.

18, lin a grinding machine, the combination ot a pair ot oppositelydisposed grinding wheels between which an article is received and bywhich the article is simultaneously ground on opposite faces, and meansfor supporting the article to be ground, said means comprising a pivotedarm, a holder to which the article to be ground may be secured, andinter nediate connections between said holder and arm that include aplurality of pivoted supporting members, the pivotal axes of which arein planes at substantially right angles one to another,

19. ln a grinding machine, the coin-bination of a pair-of oppositelydisposed grinding vf'l eels between which an article is lreceived and bywhich the article is ground on opposite faces, and means for supportingthe article to be ground, said Vmeans comprism@- a pivoted arm, a holderto which the arti `le to be ground may be secured,

and intermediate connections -between said holder and arm including asupport pivotally connected to said arm and having its pivotal axisextending at substantially right angles to said arm, a second supportpivoted on said first` mentioned support and having its pivotal axissubstantially parallel with that of the first support, and a thirdsupport which carries the holder and has its pivotal axis atsubstantially right angles to that ot the second support.

Q0. In a grinding machine, the combination ot' a pair ot oppositelydisposed grinding wheels between which an article received and by whichthe article is ground on opposite faces, and means `tor suppintingl thearticle to be ground, said means conprising a pivot-ed arm, a holder towhich the article to be ground may be secured, and intermediateconnections between said holder and arm that enable the holder toreceive a limited unrestrained movement `laterally et the arm and atdifferent angles thereto so that the article on the holder is positionedin parallelism with the grinding faces of the wheels by said Contactol.E the grinding faces therewith.

2l. ln a grinding machine the combination oi a pair of oppositelydisposed grinding wheels mounted on substantially horizontally disposedspindles, and means for supiliorting the article to'be ground betweensaid wheels, said means comprising an arm pivoted to turn on asubstantially horizontally disposed axis, a support pivotally connectedwith said arm to turn on a substantially horizontally disposed axis, asecond support pivotcd to the lirst mentioned support to turn on asubstantially horiZontallj-I,Y disposed axis, and a third support whichcarries the holder' and is pivoted to the second support. to turn on. asubstantially vertically disposed axis.

22. In a grinding machine, the combination ot' a pair of oppositelydisposed grinding wheels mounted on parallel axes and between which thearticle to be ground is received and ground on opposite sides, andautomatically operating means by which the article is introduce-dliietween said wheels; by which a relative movement of the wheelstowards each other is effected to cause them to bear against thearticle; by which the article is moved back and 'forth during thegrinding operation; by which the wheels are moved relatively away fromeach other alter the grinding operation is completed; and by which theground article is withdrawn from between the wheels.

ln grinding; machine, the combination ot a pair oit opnositely disposedgrinding wheels between which the article to be ground is received andground on opposite sides,- automat cally operating means l lli the abovedescribed cycle of operations has been effected.

24. In a grindingmacliine,the combination of a grinding wlieel,'meansfor moving said wheel against the articleto be Vground and whichincludes a positively actuated meinbei` and a resilient member throughwhich said movementis transmitted to the wheel from said positivelyactuated member, and a stop to positively arrest the said movement ofthe wheel under the action of the resilient member. i

25. In a grinding machine, the combination of a pair of grinding wheels,means for effecting a relative movement between said wheels to bringabout a contact thereof with the article tobe ground between them andwhich includes a `positively actuated member and a resilient memberthrough which said relative movement between the wheels is transmittedfrom said positively actuated member, and adjustable means forpositively arresting` and limiting said relative movement of the wheelsunder the action of said resilient member.

Q6. In a grinding machine, the combination of a pair of grinding wheels,and autoiiiatically operating means for effecting relative forward andback movements between said wheels, said means including positivelyoperatingiiioving devices, and a resilient member intermediate saidmoving devices and a part to be moved to effect the said relativemovement vof the wheels, the relative movement between the wheels inboth directions being effected by said positively operating devicesacting through saidresilient member.

27. In a grinding machine, the combination of a pair of grinding wheels,automatically operating means for effecting relative forward and backmovements between wheels, said means including positively operating`moving devices, and a resilient member intermediate said moving devicesand a part to be moved to effect the said relative movement of. thewheels and through which motion is transmitted from said positivelyopeiating` devices, and an interponent movable into and out of operativeposition and when in the operative position adapted to arrest therelative movement of said wheels towards each other and when out ofoperative position permittingthe face kof one 'wheel to be dressed bythe other.

28. In a grinding machine, the combination of a pair of grinding wheels,automatically operating means for effecting relative forward and baclrmovements between said wheels,- said means including positivelyoperating moving devices, and a resilient member intermediate saidmoving devices and a part to be moved to effect the said relativemovement of the wheels and through which motion is transmitted from saidpositively operating devices, an interponent movable into and out ofoperative position and when in the operative position adapted to arrestthe relative forward movement between said wheels, and when out ofoperative position permitting the face of one wheel to be dressed by theother, and relatively adjustable stop devices adapted to arrest suchrelative movement of the wheels when the interponent is in theinoperative position.

29. In a grinding machine, the combination of a grinding wheel,automatically operating means for ,controlling the movement of anarticle into and out of co-operative relation with the grinding wheeland forV controlling the movement'` of the wheel against and away fromthe article, and automatically operating means for disconnecting thedriving means for said firstl mentioned automatically operating meansafter its cycle of operations has been completed.

30. In a grindingmachine, the combination of a grinding wheel,automatically operv ating -means for controlling the movement of anarticle into and out of co-operative relation with the grinding wheeland for controlling the movement of the wheel against and away from thearticle;,and automatically operating means forV disconnecting thedriving means for said first mentioned autoniatically operating meansafter its cycle of operations has been completed.` said auto- .inaticdisconnect mechanism including means that enable two gears to be thrownout of mesh, means for supporting said gears in mesh, and automaticallyoperating means for releasing said supporting means.

31. In a grinding machine, the combinalitiy tion of a grinding wheel,automatically-l operating means for controlling the movement of Vanarticle into and out of co-operative relation with the grinding wheeland for vcontrolling the movement of vthe wheel against and away fromthe' article, auto-V matically operating means for disconnecting thedriving means for said first mentioned automatically operating meansafter its cycle of operations has been completed, said auto-

